This invention relates to a durable and imaged flame-retardant nonwoven fabric that can be used for wall coverings, upholstery, apparel and other related applications. Several years ago, E. I du Pont de Nemours and Company developed flame-retardant materials sold under the trademarks NOMEX(copyright) and KEVLAR(copyright). NOMEX(copyright) materials were developed for applications requiring dimensional stability and excellent heat resistance, and which do not flow or melt upon heating. Decomposition and charring does not proceed at a significant rate until well over 350xc2x0 C. without melting. NOMEX(copyright) materials in fibrous form have been used in protective apparel and similar applications, and can be processed by conventional textile technology. Heretofore, comparable flame-retardant nonwoven fabrics have been expensive to manufacture, and because such fibers are relatively slick, stiff, and do not crimp well, they have not been susceptible of imaging by high pressure water jet entangling. Specific examples of prior art materials are set forth below.
U.S. Pat. No. 4,199,642 discloses a flame resistant fiberfill batt consisting of polyester fiberfill and synthetic organic filamentary materials, including poly(m-phenylene isophthalamide) blended therewith that maintains its physical integrity when exposed to the flame from a burning match.
U.S. Pat. No. 4,463,465 discloses an aircraft seat cushion including a highly heat-sensitive urethane foam covered by a flexible matrix, which may comprise a NOMEX(copyright) fabric. A further gas barrier layer may also be provided, which can also be a NOMEX(copyright) fabric.
A wet-type survival suit is disclosed in U.S. Pat. No. 4,547,904, including inner and outer NOMEX(copyright) layers which provide maximum protection against fire.
A fire-retardant panel is disclosed in U.S. Pat. No. 4,726,987 and 4,780,359 which includes one or more layers of NOMEX(copyright) fiber that may be combined with adjacent fibrous layers by needle punching.
U.S. Pat. No. 4,748,065 discloses a flame resistant fabric, wherein a spunlaced fabric formed of fibers, such as NOMEX(copyright), is brush-coated with an aqueous slurry containing activated carbon particles. The resulting fabric was subsequently dried and softened by crepeing. Laminates, including spunlaced outer layers of NOMEX(copyright) fibers, are also disclosed.
A fire-blocking textile fabric is disclosed in U.S. Pat. No. 4,750,443 which includes a multi-layer structure consisting of three to seven nonwoven layers of hydroentangled nonwoven fabrics of poly(p-phenylene terephthalamide) and poly(p-phenylene isophthalamide) staple fibers. The layers of entangled aramid fabrics are consolidated by stitchbonding with an aramid thread.
U.S. Pat. No. 4,937,136 discloses a laminate for use in fire protective garments. The laminate includes a nonwoven fabric comprised of a blend of wool and synthetic fibers capable of high temperature performance, such as NOMEX(copyright). The laminate includes an outer shell which may also be formed of NOMEX(copyright) and an intermediate moisture barrier layer.
An animal bed cover is disclosed in U.S. Pat. No. 5,226,384, which is formed of an aramid fabric sheet, e.g. KEVLAR(copyright) with a polyester fabric sheet laminated to it.
In U.S. Pat. No. 5,252,386, a fire retardant entangled polyester nonwoven fabric is disclosed which has balanced tensile strength properties in the cross- and machine-directions and improved fire retardant properties by cross-stretching the entangled fabric, after the fabric has been wetted with an aqueous-based fire retardant composition, and drying the wetted fabric while maintaining it in its stretched state.
U.S. Pat. No. 5,279,879 discloses a flame-retarding nonwoven fabric formed of partially graphitized polyacrylonitrile fibers that are bonded by water jet needling. The fabric may be reinforced by warp-wise and weft-wise threads, and the fabric may be combined with a decorative fabric/material by adhesive securement.
U.S. Pat. No. 5,475,903 discloses a fabric that is formed by carding synthetic fibers, such as polyester fibers, cross-lapping the carded web to orient the fibers in the cross-direction, drafting the cross-lapped web to reorient certain of the fibers in the machine-direction, applying unbonded wood fibers to the top of the drafted web, and hydroentangling the resulting web to entangle the wood fibers with those of the polyester drafted web. A liquid fire-retardant composition is then applied to the hydroentangled web.
In U.S. Pat. No. 5,578,368, a fire-resistant material is disclosed, which includes a fiberfill batt, that may comprise polyester fibers, and a fire-resistant aramid fibrous layer like NOMEXI(copyright), at one, or both, faces of the batt. The aramid fiber layer may be joined to the fiberfill batt by hydroentangling.
U.S. Pat. Nos. 5,609,950 and 5,766,746 disclose a flame-retardant nonwoven fabric wherein fleece, including cellulose fibers having a flame-retardant containing phosphorus, is bonded by water jet entanglement.
From the foregoing, it is clear that the prior art lacks a teaching of an imaged flame-retardant nonwoven fabric, and particularly such a fabric that is relatively low in cost by virtue of lamination by water jet entanglement of one or more relatively low cost webs with a relatively high cost flame retardant web, such as NOMEX(copyright), or the like.
The fabric of the present invention is a laminate including a first layer formed of dimensionally stable, heat-resistant fibers, such as NOMEX(copyright) fibers commercially available from E. I. du Pont de Nemours and Company. While the heat and flame-resistant properties of such fibers are well understood and appreciated, commercialization of products incorporating such fibers to-date has been somewhat limited, because such fibers are sufficiently high in cost that manufacturers of commercial products wherein heat and flame-resistance are important have sought less costly alternatives. The present invention overcomes this problem by using a relatively low basis weight NOMEX(copyright) layer, and bonding thereto a lower cost support layer having a higher basis weight. The lower cost layer provides support and basis weight required to form the high volume, three-dimensional pattern in the layer of NOMEX(copyright) fibers. The resulting laminate is a relatively heavy weight fabric that is imaged on a three-dimensional support surface to incorporate aesthetic appeal to at least the NOMEX(copyright) layer. In use, it is intended that the layer formed of heat-resistant fibers, rather than the support layer, face the flame source. The resulting laminate has a fire-retardant binder applied thereto to stabilize the image, provide enhanced durability, and improve the flame-retardant characteristics of the laminate.